Quick SWR Calculator for Vertical and Dipole Ham Radio Antennas

Here’s a really simple way of double checking how to much to trim your antenna elements.

You only need to type in the numbers in the Cyan boxes.

  • For Dipoles: Cut / Add the result to each leg
  • For Verticals: Cut / Add result to your vertical radiator

Just type in where it is resonant right now – then type in where you would like it to be resonant and the spreadsheet will auto-calculate the trimming.

 

* Thank you to Aubrey (AubsUK on YouTube) for the Online version below:

Resonant Now

Frequency that gives a perfect resonance
 (MHz) 
WaveWavelength of the resonant frequency
¼-WaveQuarter wavelength of the resonant frequency
LengthTotal length of all elements for the resonant frequency

Aiming for

Target frequency for perfect resonance
 (MHz) 
WaveWavelength of the target frequency
¼-WaveQuarter wavelength of the target frequency
LengthTotal length of all elements for the target frequency